1. Field of the Invention
The present intention relates to method and apparatus for measuring various dimensions of parts or products manufactured with a sheet metal machine tool or unit. Further, the present invention relates to a sheet metal processing system which uses such measuring method and apparatus.
2. The Prior Art
Up to now, an in-plant worker or inspector would use a measuring device, such as calipers, a micrometer, a protractor or a three-dimensional measuring device, to measure various sites or portions of a product or part manufactured with a sheet metal machine tool, in order to determine whether or not the manufactured product or part was manufactured in accordance with prescribed specifications.
Now, when such measurements are to be carried out, the worker or inspector must determine the specific sites or dimensions to be measured based on instructions and drawings in a job instruction manual. However, because a considerable amount of experience is required to appropriately determine such measurement sites or dimensions, an inexperienced worker is likely to make mistakes. Furthermore, when carrying out measurements, an inexperienced worker may choose the wrong measuring device. Moreover, even if the correct measuring device is selected, an inexperienced worker may use such measuring device incorrectly (e.g., improper placement of the protractor on the manufactured product being inspected).
Furthermore, because the measurement data and results must be entered in a book with hand when using measuring devices in accordance with prior art methods, the handwriting process is very time-consuming and susceptible to errors (e.g., an incorrect entry in the book). Moreover, because a considerable amount of experience is required in order to judge whether or not a manufactured product or part is acceptable based on such measurement data, an experienced worker will have difficulty in determining the acceptability of a manufactured product or part. In this connection, because the technical level of in-plant worker is becoming more diversified, there is an increasing chance of errors occurring due to inexperienced workers being required to perform inspection of manufactured products or parts.
JP 4-164550A discloses a method in which dimensions of the product or part manufactured by a machine tool are measured by a measuring device, and the measured dimensions are sent to an NC device. In the NC device, the data is used to evaluate the quality of the products and to revise the NC data if the quality is unsatisfactory. Even in this method, it is still difficult for the worker or inspector to determine the appropriate specific sites or dimensions of the product or part to be measured.